A 12-year-old female presents with a caregiver who is worried that the child has not developed breasts. The caregiver says that in their family, every female had menarche by age 12. The adolescent eats a well-balanced diet and is generally healthy. On exam, the child is in the 25th percentile for height and the 10th to 25th percentile for weight. This is consistent with her growth charts at previous wellness checks. She is nondysmorphic and well-appearing. She has tanner stage two breast development and pubic hair. What is the proper response to the caregiver’s concerns? A. Referral to endocrinology for delayed puberty B. Karyotype, bone age, LH, FH, and estradiol measurement C. Reassurance that the patient has started puberty and close follow-up D. Referral to GI for workup of occult GI disease